.024 cold would be something like.028-.030 hot in my experience. That is very loose in my opinion. Are you saying that you usually run it looser?

The design specs for the lash are 28/32.

I’m not saying there aren’t combos that wouldn’t respond to tighter settings, but tighter will have you opening the valves on the clearance ramps.

Looser lash settings really speed up the valves movement off the seat....... although it’s usually a little harder on parts.

The reason I asked was that if they were tightened to 24 cold what are they normally at? How much tighter was it to take 2 tenths out of the car? I've always had trouble at some point +.030 lash. Even with the old Mopar solids.

You really wouldn’t have liked some of the old Cam Dynamic rollers with the recommended lash of .035.

Even the old stock Chevy Duntov cam was .030(That’s why it’s referred to as the 30-30 cam).

Yeah I've learned this lesson the hard way several times over the years. Certain cylinder heads prefer certain lobes. Guys who work with the same engine combination over and over gradually acquire this knowledge. Guys sitting on the tech line at a cam company may or may not have any knowledge of the specific cylinder head being used.

If I call Comp Cams I'll get a cam recommendation that is very close in terms of duration but typically the lobe family won't be spot on.

The 590 is one of those old school cams that works great when it is paired up with the matching parts. I used one once a long time ago and it ran hard but we used it with some old school heads and intake.

I usually lash it to 26/30 cold which is 75 degrees at least. I don't get this motor over 160 degrees normally or it starts picking up numbers.


Hutch

Correction: The Duntov cam was the 097 cam which had right at 0.4" lift. He actually made the previous cam just a little bit smaller so it would rev better.

The 30-30 cam, while mistakenly called a Duntov, wasn't designed by Zora. it had something like 252 duration at 50 and had gross lift of 0.485 which turned into 0.455 after the lash was subtracted.

If you care to read about Chevy cams, this article lays it out nicely. https://www.enginelabs.com/engine-tech/cam-valvetrain/duntov-small-block-camshaft/

I was deep into chevies back in the day and back then nobody called the 30-30 cam a Duntov anything. For many people's money, the Chevy cam to use in something less than a nearly race engine was the 3863151 cam, the 350 horse 327 hydraulic cam. Mine cost me $38 plus tax at Rydell Chevrolet in Grand Forks.

R.

Good read.

Interesting how they used a different core for each cam part number to minimize the grinding time.

I seem to remember one of the Mopar tech line guys telling me many years ago that Mopar had switch vendors, cam grinders on all their cams and the one I was calling on complaining about not having the advertised lift was due to the vendors not grinding them correctly.
He also said later that Mopar had two different specs. throughout the life of the "590" grind, LSA being different as well as on lobe lift
Any one else seen or heard of this?
OP, I use to use a Isky grind, .616/.590 split duration cam for BB Mopars ground on a 104 LSA, that was similar to the original Mopar "590 grind.
that cam worked very well installed from straight, 104 ILC, up to being advanced to 99 BTDC on the ILC

a lot depends on the combo. He can try both loose and tight. My deal, a stroked 440, loved tight lash cause IT was way under cammed. If his motor is shifted at a higher rpm with a looser converter, it might love tight lash.

My old $800.00 4 speed V code 440 had a crane solid 590 cam .030 over and 13.1 pistons and was a monster but didn't want to idle much under 1500. Can't remember the lash but that was 44 years ago.